Todd K. Fuller

FAST‐TRACK: A southern California freeway is a physical and social barrier to gene flow in carnivores

Roads present formidable barriers to dispersal. We examine movements of two highly mobile carnivores across the Ventura Freeway near Los Angeles, one of the busiest highways in the United States. The two species, bobcats and coyotes, can disappear from habitats isolated and fragmented by roads, and their ability to disperse across the Ventura Freeway tests the limits of vertebrates to overcome anthropogenic obstacles. We combine radio‐telemetry data and genetically based assignments to identify individuals that have crossed the freeway. Although the freeway is a significant barrier to dispersal, we find that carnivores can cross the freeway and that 5–32% of sampled carnivores crossed over a 7‐year period. However, despite moderate levels of migration, populations on either side of the freeway are genetically differentiated, and coalescent modelling shows their genetic isolation is consistent with a migration fraction less than 0.5% per generation. These results imply that individuals that cross the freeway rarely reproduce. Highways and development impose artificial home range boundaries on territorial and reproductive individuals and hence decrease genetically effective migration. Further, territory pile‐up at freeway boundaries may decrease reproductive opportunities for dispersing individuals that do manage to cross. Consequently, freeways are filters favouring dispersing individuals that add to the migration rate but little to gene flow. Our results demonstrate that freeways can restrict gene flow even in wide‐ranging species and suggest that for territorial animals, migration levels across anthropogenic barriers need to be an order of magnitude larger than commonly assumed to counteract genetic differentiation.

Pathogens, Nutritional Deficiency, and Climate Influences on a Declining Moose Population

Abstract Several potential proximate causes may be implicated in a recent (post-1984) decline in moose (Alces alces andersoni) numbers at their southern range periphery in northwest Minnesota, USA. These causes include deleterious effects of infectious pathogens, some of which are associated with white-tailed deer (Odocoileus virginianus), negative effects of climate change, increased food competition with deer or moose, legal or illegal hunting, and increased predation by gray wolves (Canis lupus) and black bears (Ursus americanus). Long-standing factors that may have contributed to the moose decline include those typically associated with marginal habitat such as nutritional deficiencies. We examined survival and productivity among radiocollared (n = 152) adult female and juvenile moose in northwest Minnesota during 1995–2000, and assessed cause of death and pathology through carcass necropsy of radiocollared and non-radiocollared animals. Aerial moose surveys suggested that hunting was an unlikely source of the numerical decline because the level of harvest was relatively low (i.e., approx. 15% / 2 yr) and the population usually grew in years following a hunt. The majority of moose mortalities (up to 87% of radiocollared moose [n = 76] and up to 65% of non-radiocollared moose [n = 84]) were proximally related to pathology associated with parasites and infectious disease. Liver fluke (Fascioloides magna) infections apparently constituted the greatest single source of mortality and caused significant pathology in the liver, thoracic and peritoneal cavities, pericardial sac, and lungs. Mortality due to meningeal worm (Parelaphostrongylus tenuis) was less prevalent and was manifested through characteristic neurological disease. Several mortalities apparently were associated with unidentified infectious disease, probably acting in close association with malnutrition. Bone-marrow fat was lower for moose dying of natural causes than those dying of anthropogenic factors or accidents, implying that acute malnutrition contributed to moose mortality. Blood profiles from live-captured animals indicated that those dying in the subsequent 18 months were chronically malnourished. Relative to other populations, average annual survival rates for adult females (0.79 [0.74–0.84; 95% CI]) and yearlings (0.64 [0.48–0.86]) were low, whereas those for calves (0.66 [0.53–081]) were high. Pregnancy (48%) and twinning (19%) rates were among the lowest reported for moose, with reproductive senescence among females being apparent as early as 8 years. Pregnancy status was related to indices of acute (i.e., bone-marrow fat) and chronic (i.e., blood condition indices) malnutrition. Opportunistic carcass recovery indicated that there likely were few prime-aged males (>5 yr old) in the population. Analysis of protein content in moose browse and fecal samples indicated that food quality was probably adequate to support moose over winter, but the higher fecal protein among animals that died in the subsequent 18 months could be indicative of protein catabolism associated with malnutrition. Trace element analysis from moose livers revealed apparent deficiencies in copper and selenium, but there was limited evidence of direct association between trace element concentrations and moose disease, pathology, or mortality. Time-series analysis of regional moose counts (1961–2000) indicated that annual population growth rate was related negatively to mean summer temperature, with winter and summer temperatures increasing by an average of 6.8 and 2.1 C, respectively, during the 40-year period. This change may have increased moose thermoregulatory costs and disrupted their energy balance, and thereby reduced their fitness. Time-series analysis failed to show a relationship between annual population growth rate and moose or deer abundance, indicating that food limitation via resource competition was unlikely. Population viability analyses, using count data (1961–2000) and demographic data collected during this study, suggested that the northwest Minnesota moose population likely would not persist over the next 50 years. More broadly, we conclude that the southern distribution of moose may become restricted in areas where climate and habitat conditions are marginal, especially where deer are abundant and act as reservoir hosts for parasites.

Infectious disease and the conservation of free‐ranging large carnivores

Abstract Large carnivores are of vital importance to the stability and integrity of most ecosystems, but recent declines in free‐ranging populations have highlighted the potentially devastating effect of infectious diseases on their conservation. We reviewed the literature on infectious diseases of 34 large (maximum body mass of adults >20 kg) terrestrial carnivore species, 18 of which are considered to be threatened in the wild, and examined reports of antibody prevalence (seroprevalence) and cases of infection, mortality and population decline. Of 52 diseases examined, 44% were viral, 31% bacterial and the remainder were protozoal or fungal. Many infections were endemic in carnivores and/or infected multiple taxonomic families, with the majority probably occurring via inhalation or ingestion. Most disease studies consisted of serological surveys for disease antibodies, and antibody detection tended to be widespread implying that exposure to micro‐organisms was common. Seroprevalence was higher in tropical than temperate areas, and marginally higher for infections known to occur in multiple carnivore groups. Confirmation of active infection via micro‐organism recovery was less common for ursids than other taxonomic groups. Published descriptions of disease‐induced population decline or extinction were rare, and most outbreaks were allegedly the result of direct transmission of rabies or canine distemper virus (CDV) from abundant carnivore species to less‐common large carnivores. We conclude that the threat of disease epidemics in large carnivores may be serious if otherwise lethal infections are endemic in reservoir hosts and transmitted horizontally among taxa. To prevent or mitigate future population declines, research efforts should be aimed at identifying both the diseases of potential importance to large carnivores and the ecological conditions associated with their spread and severity.

Population Dynamics of African Wild Dogs

The reasons African wild dog (Lycaon pictus) populations declined to endangered status continent-wide have been difficult to document. However, demographic research to date indicates the following. Annual pack range size (150–3800 km2), density (2–35 dogs/1,000 km2), and territorial propensity of wild dogs appear related to prey density and temporal distribution, and habitat structure. Wild dogs usually live in packs of 10–14 composed of 1 or more adult females unrelated to 1 or more adult males, and their current or older offspring. Sex ratios of adults, yearlings, and pups usually are skewed toward males. Annually, usually 1 but sometimes 2 pack females breed and produce 8–12 pups each (up to 23 total); timing and frequency of parturition appears to coincide with prey abundance. Annual adult survival usually ranges from 0.65–0.85 and likely is most influenced by human-related mortality factors and disease (e.g., rabies and anthrax). Pup survival (0.1473x2013;0.73) appears to be influenced by number of adults in the pack and food availability. Dispersing wild dogs usually do so with same-sex siblings when 1.0–2.0 years old. Nutritional factors and perhaps natal pack composition likely affect the rates at which male or female wild dogs disperse. Dispersing groups join established packs or meet up with opposite sex groups and settle to establish new packs; dispersal distances may exceed 200 km. Observed annual finite rates of increase (k) for African wild dogs have ranged from 0.83–1.77, but potential rates may exceed 2.0. Reduced adult mortality, coupled with high pup survival and their subsequent dispersal as yearlings, can provide a mechanism by which populations decimated by catastrophic disease or human destruction can quickly rebuild if sufficient habitat is available. Collaborative ongoing research throughout a variety of habitats in Africa will facilitate examination of wild dog population dynamics, and provide information critical to conservation efforts.

Assessing Estimators of Snow Leopard Abundance

Abstract The secretive nature of snow leopards (Uncia uncia) makes them difficult to monitor, yet conservation efforts require accurate and precise methods to estimate abundance. We assessed accuracy of Snow Leopard Information Management System (SLIMS) sign surveys by comparing them with 4 methods for estimating snow leopard abundance: predator:prey biomass ratios, capture–recapture density estimation, photo-capture rate, and individual identification through genetic analysis. We recorded snow leopard sign during standardized surveys in the SaryChat Zapovednik, the Jangart hunting reserve, and the Tomur Strictly Protected Area, in the Tien Shan Mountains of Kyrgyzstan and China. During June–December 2005, adjusted sign averaged 46.3 (SaryChat), 94.6 (Jangart), and 150.8 (Tomur) occurrences/km. We used counts of ibex (Capra ibex) and argali (Ovis ammon) to estimate available prey biomass and subsequent potential snow leopard densities of 8.7 (SaryChat), 1.0 (Jangart), and 1.1 (Tomur) snow leopards/100 km2. Photo capture–recapture density estimates were 0.15 (n = 1 identified individual/1 photo), 0.87 (n = 4/13), and 0.74 (n = 5/6) individuals/100 km2 in SaryChat, Jangart, and Tomur, respectively. Photo-capture rates (photos/100 trap-nights) were 0.09 (SaryChat), 0.93 (Jangart), and 2.37 (Tomur). Genetic analysis of snow leopard fecal samples provided minimum population sizes of 3 (SaryChat), 5 (Jangart), and 9 (Tomur) snow leopards. These results suggest SLIMS sign surveys may be affected by observer bias and environmental variance. However, when such bias and variation are accounted for, sign surveys indicate relative abundances similar to photo rates and genetic individual identification results. Density or abundance estimates based on capture–recapture or ungulate biomass did not agree with other indices of abundance. Confidence in estimated densities, or even detection of significant changes in abundance of snow leopard, will require more effort and better documentation.

Serologic survey of selected canine pathogens among free-ranging jackals in Kenya

Serum samples from 76 free-ranging adult jackals of three species from four localities in Kenya were examined for circulating antibodies against four canine pathogens: rabies virus, canine parvovirus (CPV-2), canine distemper virus (CDV), and Ehrlichia canis. Samples were collected between April 1987 and January 1988. Among black-backed jackals (Canis mesomelas), the most sampled species, the mean prevalence of antibodies to CPV-2, CDV, rabies virus, and E. canis was 34% (14 positive/55 sampled), 9% (4/55), 3% (1/28), and 2% (1/36), respectively. There were no significant differences among sampling locations. In one area, antibody prevalence of CPV-2 was significantly higher for golden jackals (C. aureus; 9/16) than for C. mesomelas (5/26). Only three side-striped jackals (C. adustus) were sampled, but antibodies to CPV-2 and CDV were present. As jackals often are the most abundant wild carnivore in African ecosystems, they could serve as an important indicator species to monitor the potential of exposure of rare and endangered canids to specific canine diseases.

Movements and activities of white-lipped peccaries in Corcovado National Park, Costa Rica

Abstract The conservation of remnant populations of white-lipped peccaries in Central America depends on adequate documentation of their habitat needs and behavior. Thus, we monitored the activity patterns, local distributions, and home ranges of 36 (25F:11M) radio-marked white-lipped peccaries, all members of a single “super” herd, in part of Corcovado National Park, their largest stronghold in Costa Rica, during 1996–1998. Peccaries were diurnal all year with a period of reduced activity during the middle of the day. They were found more often than expected (vs. random use) in primary forest during February to May, in secondary and coastal forest during June to September, and in herbaceous swamp during October to January, corresponding to relative fruit abundance. Overall, the peccary herd ranged over an area of 2 , but use of the area shifted seasonally and movements were reduced when fruit was most abundant. Our data agree with the suggestion that peccary density may be higher where the interspersion or close proximity and mix of seasonally important habitats is high, and thus where peccaries do not have to travel as far for food. Habitat interspersion is therefore a significant conservation concern and should be addressed to make certain that peccary populations are not limited.

Estimating the population density of Mongolian gazelles Procapra gutturosa by driving long-distance transects

in autumn, with total population estimates of 803,820 (483,790–1,330,100 95% confidence interval) and 870,625 (499,432–1,491,278 95% confidence interval), respectively. Confidence limits were wide, and to obtain a coefficient of variation of 20%, transect lengths would need to be extended three- to four-fold. Until more efficient means for conducting population surveys can be implemented, driving long-distance transects, combined with distance analysis, seem to provide the best quantitative estimate of Mongolian gazelle populations.

Evaluation of a Simulated Howling Survey for Wolves

Wolf (Canis lupus) packs were surveyed using simulated howling survey (Harrington and Mech 1982) in a 1,400-km2 area of northcentral Minnesota with a known density of radio-marked packs. Mean distance that wolf howls could be heard was 2 km (n = 74 trials). Howling at 55 sites indicated the presence of 5 packs and resulted in a density estimate (7.5 packs/1,000 km2) that was imprecise (95% CI = 2.5-16.4/ 1,000 km2) and 1.7x greater than the actual density (4.3/1,000 km2). Because of logistical and statistical constraints, the technique is not practical for surveying large (e.g., stateor province-wide) areas, but simulated howling is useful for locating packs in smaller areas. J. WILDL. MANAGE. 52(1):60-63 Simulated howling (D. H. Pimlott, Midwest Fish and Wildl. Conf. 22, Toronto, Can., 1960) has been used to locate wolves and estimate changes in wolf pack numbers (Theberge and Strickland 1978), but not always with success (Crete and Messier 1987). Harrington and Mech (1982) analyzed factors influencing responses to simulated howling and presented recommendations for the use of simulated howling as a census technique for small (saturation census) and large areas (sampling census). They did not, however, explore logistical constraints, determine the mean radius of audibility from sampling sites, or verify the accuracy or precision of estimates of the number of packs. Our study evaluated the efficacy of simulated howling, using the sampling census design of Harrington and Mech (1982), in surveying a wolf population of known density in northcentral Minnesota. Funding was provided by the U.S. Fish and Wildlife Service, Office of Endangered Species, and the Minnesota Department of Natural Resources (MDNR), Section of Wildlife, and supported by the Forest Wildlife Populations and Research Group, MDNR. We are grateful for the field assistance of D. W. Kuehn, P. L. Coy, and A. C. Larsen, and the statistical advice of R. M. Pace. D. L. Garshelis, D. W. Kuehn, F. H. Harrington, L. D. Mech, R. E. Lake, J. B. Theberge, and 2 anonymous referees reviewed the manuscript and provided helpful suggestions for improvement.

Rural and suburban forest edges: effect on egg predators and nest predation rates

Abstract Although the observed declines of many species of Neotropical migratory birds have been linked to losses in the wintering grounds, it is important to examine sources of mortality from all portions of the annual cycle to fully understand migratory bird declines. Forest fragmentation and the creation of new forest edges have been implicated as factors contributing to increased nest predation rates on the breeding grounds. We selected four forests with edges in suburban settings, and four forests with edges in rural settings, to determine if nest predation rates differed with human density. From 1993 to 1994 we used two types of automatic photographic systems and artificial nests baited with quail eggs to measure predation rates on ground- and shrub nests at points 20–420 m from the forest edges. Rural-edged forests experienced significantly higher nest predation rates than did suburban-edged forests. Only three species, blue jay, raccoon, and black bear, were responsible for virtually all of the predation events. While blue jays appeared to be unaffected by forest edge type, there were more bear predations in rural-edged forests and more raccoon predations in suburban-edged forests. There were no significant differences in predation rate between nest types or in species-specific rates of predation on the two nest types. We suggest that future studies of nest predation include the identification of predators to give scientists greater insight into the predation process.